[Checkins] [zopefoundation/zope.index] 7e90e4: Fix error case of FieldIndex.

[GitHub]

  Branch: refs/heads/icemac-patch-1
  Home:   https://github.com/zopefoundation/zope.index
  Commit: 7e90e4fed78e694c376f047fa5b87fafaddf12f7
      https://github.com/zopefoundation/zope.index/commit/7e90e4fed78e694c376f047fa5b87fafaddf12f7
  Author: Michael Howitz <mh at gocept.com>
  Date:   2017-03-23 (Thu, 23 Mar 2017)

  Changed paths:
    M src/zope/index/field/index.py

  Log Message:
  -----------
  Fix error case of FieldIndex.

Make sure the query is iterable in first place before computing its length to geht the expected TypeError.